Thank you again for your help AndrewAMD! dataDownload works for getting the data.
However, I just figured out how to get the regular code to work:
assetHistory(strf("WIKI/%s",Loop1),FROM_QUANDL);
instead of
assetHistory(Loop1,FROM_QUANDL);
does the trick. Would have been nice if this was shown in one of the examples in the manual.